The suspension system of an automobile allows the automobile to drive smoothly over a bumpy surface. The wheels may jolt up and down, but the suspension system between the wheel assemblies and the body and frame of the vehicle flex and take up the force of the jolt. The suspension system insures that the force of the jolt does not transfer to the vehicle and its occupants. Springs alone produce a bouncing motion, so the suspension system also contains dampers, commonly known as shock absorbers. The shock absorbers slow the movement of the springs to prevent the car and its occupants from bouncing up and down.
Many types of springs have been utilized in the automotive industry in numerous configurations. In particular, coil springs have been utilized in smaller vehicles which have a coil spring and shock absorber attached to each wheel. The spring and shock absorber are fixed between the car body and the wheel struts.
Larger vehicles often utilize heavy-duty leaf springs and shock absorbers to cushion the ride. The leaf spring is a stack of steel strips slightly curved so that the spring straightens when the vehicle is loaded. The ends of the spring are fixed to the vehicle frame or body and the shock absorber is fixed between the axle and the vehicle body.
Torsion bars are steel rods that act like a spring to take up a twisting force. If the bar is forced to twist in one direction, it resists the movement and then twists back when the force is removed. Many cars contain an anti-roll bar fixed between the front axles. This rotates as the wheels go up and down. If the car begins to rollover on a tight corner, the anti-roll bar prevents the roll from increasing.
Each of the above-spring systems which are utilized in various vehicle suspensions have different mounting requirements. In particular, the use of coil springs between a strut and a vehicle body requires that the vehicle body be substantially rigid in the location of the connection to the coil spring. In addition, the space required for a vertical coil spring and shock absorber assembly can greatly limit the design flexibility for a vehicle. The use of leaf springs and torsion bars also have design limitations and restrictions which may require frame cross members which restrict the space available for luggage, fuel tank, spare tires, etc. Accordingly, it is desirable in the automotive industry to provide a suspension system which is compact and allows for greater vehicle design flexibility.